US 2013/0117581 A1 discloses a method, in which a first device provides a first power to a second device using a first set of conductors out of a plurality of conductors. The first device provides, in response to receiving a notification, a second power to the second device using the first and a second set of conductors out of a plurality of conductors. The notification indicates that the second device can be supplied with a second power using the first set of conductors and a second set of conductors out of the plurality of conductors, and can also specify the configuration for enabling the second power. “Mixed lines” for both power delivery and data transmission in the context of power negotiation are described and used as follows. At a start of the power negotiating protocol, an initial power is provided to a load device by a power supply using a first set of conductors. A power negotiating protocol may be initiated upon first coupling the load device and the power supply, or when being turned on after being in a power-off state. Once the load device receives this initial power, it can send a notification to the power supply using their connection via the first set of conductors. This notification can indicate that the load device can be supplied with a second power using a second set of conductors. The power supply can then provide a second power to the load device using both the first and second sets of conductors.